Structural and electronic properties of single-side fluorinated graphene C4F under equibiaxial strains

We investigate the structural and electronic properties of the single-side fluorinated graphene C4F supercell under equibiaxial strains via first-principles calculations. The results show that, the fluorinated and non-fluorinated C atoms (CA and CB) have two C–C bonds (CA–CB and CB–CB) whose lengths decrease (increase) with increasing equibiaxial compressive (tensile) strain. Due to adsorption of F on CA, the bond angle of three adjacent C atoms CB–CA–CB is always smaller than CA–CB–CB under the same strain. The unstrained C4F supercell exhibits a direct band gap and undergoes the direct-to-indirect transition by applying equibiaxial compressive strains. While the band gap of C4F supercell increases slightly with the increasing equibiaxial tensile strain.